From the prior art, countless eyeglass frames are known which use different types of joint mechanisms. The most common variant is based on a hinge mechanism where pins are arranged on the frame and/or the mount which cooperate with a corresponding joint part which is arranged on the mount-side end of the temple, wherein the two parts are pushed together and are rotatably-connected by means of special screws. With most frames, especially those which are to be used with corrective lenses, the opening and closing of the mount takes place by means of a so-called locking block. It is also conceivable that lenses are directly attached to a frame, where screws are directly screwed into the lens. In the case of frameless eyeglasses, the temples are screwed directly into the lenses via an extension piece.
Since the pivot joint represents the most dynamically stressed component of an eyeglass frame, several solutions have done away with a conventional pivot joint for simplicity reasons.
For example, U.S. Pat. No. 3,155,982 proposes a pair of eyeglasses, in which the eyeglass temples interact directly with the front part of the mount holding the lenses. For this, the mount-side end of the temple is divided into three leaf springs, wherein the middle leaf spring abuts the outer edge of the mount part, whereby the two outer leaf springs are using hooks formed at their ends, which engage in openings which are arranged in the main part near to the outer edge.
A similar mechanism is known from the French Patent No. 1009345. In the eyeglass frame disclosed there, the temples are similarly divided into three leaf springs on the ends which taper on the mount. On the mount itself, a U-shaped extension piece is provided on the left and right, the central part of which forms a joint, in which the end bent into the shape of a hook engages the middle of the three leaf springs. The two outer leaf springs run straight along their entire length wherein, when the temples are unfolded, their ends abut with the side surfaces on the side of the extension piece turned away from the wearer and with the front faces on the surface of the eyeglass mount facing the wearer, whereby the temples are stabilised in an unfolded state.
A simpler design is proposed in European Patent No. 0 863 424 B1, which integrates the solution related to the joint connection which is already integrated in the frame and/or the mount and which adopts the principle of a temple which is provided with three leaf springs. A connection element is provided on the mount, on the left and right hand side respectively. This comprises an upper and a lower recess which constitutes a joint axis running perpendicular to the direction of the unfolded temple. When the temples are unfolded, the outer leaf springs abut the surface of the connecting element which is facing the wearer and clamp the recesses in the connecting element with bends which are provided on their free ends. At the same time, the middle leaf spring abuts the opposite surface of the connecting element. Thus, in a simple way, a joint is created which engages the mount directly and does away with conventional types of connections such as screws. In so doing, the connecting element is divided into two so as to allow easy replacement of the lenses. All component parts of such eyeglasses are made of sheet metal. This mechanism, however, is afflicted with the disadvantage that the mount and/or the frame must be made of the same material as the connecting elements, as these connection elements are integrally connected to the frame.
From the German patent application No. 10 2005 019 850 A1, an eyeglass frame is known of, in which in each case, a receiving element is provided on both sides of the frame which is fully embraced by two clips of a connecting element for the temple, wherein the clips are received in corresponding grooves which are provided on the outer surfaces of the receiving element.